Move docs to a separate directory

doc/config-file.md

@@ -0,0 +1,45 @@
+# Configuration file
+
+gamja can be configured using a `config.json` file at the root. Example:
+
+```json
+{
+	"server": {
+		"url": "wss://irc.example.org",
+		"autojoin": "#gamja"
+	},
+	"oauth2": {
+		"url": "https://auth.example.org",
+		"client_id": "asdf"
+	}
+}
+```
+
+## IRC server
+
+The `server` object configures the IRC server.
+
+- `url` (string): WebSocket URL or path to connect to. Defaults to `/socket`.
+- `autojoin` (string or array of strings): Channel(s) to automatically join
+  after connecting.
+- `auth` (string): configure how the password UI is presented to the user. Set
+  to `mandatory` to require a password, `optional` to accept one but not
+  require it, `disabled` to never ask for a password, `external` to use SASL
+  EXTERNAL, `oauth2` to use SASL OAUTHBEARER. Defaults to `optional`.
+- `nick` (string): default nickname. If it contains a `*` character, it will be
+  replaced with a random string.
+- `autoconnect` (boolean): don't display the login UI, immediately connect to
+  the server
+- `ping` (number): interval in seconds to send PING commands. Set to 0 to
+  disable, this is the default. Enabling PINGs can have an impact on client
+  power usage and should only be enabled if necessary.
+
+## OAuth 2.0
+
+The `oauth2` object configures OAuth 2.0 authentication.
+
+- `url` (string): OAuth 2.0 server URL. The server must support OAuth 2.0
+  Authorization Server Metadata (RFC 8414) or OpenID Connect Discovery.
+- `client_id` (string): OAuth 2.0 client ID.
+- `client_secret` (string): OAuth 2.0 client secret.
+- `scope` (string): OAuth 2.0 scope.